p1050 p1062 Limp mode issues

[petew19]

So I have owned my 2006 2.0si z4 (96,000 miles) for the last few months and I have repeated issues with the EML light popping on with a slightly rough idle. I ran the codes through an OBD reader and came back with the codes p1050 p1062.

These codes have been discussed in a previous thread but no solution seemed to be found. The codes refer to the valvetronic system in particular a power/communication problem with the valvetronics not the vanos so my first move was to take out the vanos solenoids for inspection.

When I took the solenoids out, they did not appear to be clogged up and I gave them a good clean out with carb cleaner cycling on and off hooked up to an old battery. I also gave the connectors a clean with contact cleaner as there appeared to be some oil leak around the solenoids. I also flipped out the O-rings to prevent further leaks.

Now, 2 weeks later I take the car out and mid drive I just have a sudden dip in power and the engine light switches on. I take the car back and the same two codes p1050, p1062. When I clear the codes the car drives fine again but it still has a rough idle and sometimes can be slightly jolty in pulling away in low gears. It seems that there is some connectivity issue driving the car to switch to limp mode but I'm not sure why.

I just wanted to get an idea from you guys on the forum what you suggest I try next. I did try purchase new solenoids but they were branded non OEM which the car immediately rejected (buying cheap never works!). My thoughts next is to try either replace the solenoids with new OEM parts if there is some issue with the connectivity of the current solenoids but my reservation is that the current solenoids work and do not appear to be blocked.

If you guys have any ideas it would be greatly appreciated as I am fairly new to this!

 

[Jfgoldfish]

The codes you are seeing do typically relate to the valvetronic system rather than the VANOS. I don't think your money would be well spent buying new VANOS solenoids unless you can prove the current ones to be faulty.

How are you reading the codes? It might be worthwhile seeing if someone in your area is able to plug it into INPA or ISTA to check for BMW specific codes and take a look at the live sensor data.

The valvetronic system is made up of a stepper motor that drives a eccentric shaft via a worm gear. The shaft has a sensor on the end called the eccentric shaft sensor. (Sorry if I'm teaching grandma to suck eggs here)
Worth checking and cleaning the connector on the motor and checking the eccentric shaft sensor connector for oil contamination. Oil in the ESS connector calls for replacement.
If you have a multimeter, check the resistance of the valvetronic motor, I believe it should be a few (5-6) ohms off the top of my head.

 

[petew19]

Cheers mate, really appreciate the help. Just reading with a OBD Torque app so low tech stuff. I'll try get the cover off and have a look at the ESS this weekend. My thought is that I've got oil in one of the sensors but just trying to locate where. Have you had any experience with VDO eccentric shaft sensors or would you recommended just sticking with OEM?

 

[Jfgoldfish]

Have you had any experience with VDO eccentric shaft sensors

I believe VDO is the OE manufacturer for the ESS. If it does need replacing, go with VDO, not cheap junk.
Normally they throw various other codes when read with BMW specific software.



The ESS can be seen on the end of the eccentric shaft in this image.
The motor connector can be seen under the motor there. I would recommend checking that connection.

I would highly recommend asking someone with INPA/ISTA to read the codes or setting the software up yourself. It can be a very valuable tool when chasing issues like this.

My advice would be, be maticuluous, don't discount failing crimped connectors. I had a failing crimp on my wiring loom, it was an absolute pain to find.
Blindly replacing components can quickly empty a wallet in this situation. I think that is why the previous owner sold the car (my car)!